Borate and phosphite treatments of potato plants (Solanum tuberosum L.) as a proof of concept to reinforce the cell wall structure and reduce starch digestibility.

Potatoes are one of the main sources of carbohydrates in human diet, however they have a high glycaemic index (GI). Hence, developing new agricultural and industrial strategies to produce low GI potatoes represents a health priority to prevent obesity and related diseases. In this work, we investigated whether treatments of potato plants with elicitors of plant defence responses can lead to a reduction of tuber starch availability and digestibility, through the induction of cell wall remodelling and stiffening. Treatments with phosphites (KPhi) and borate were performed, as they are known to activate plant defence responses that cause modifications in the architecture and composition of the plant cell wall. Data of suberin autofluorescence demonstrated that potato plants grown in a nutrition medium supplemented with KPhi and borate produced tubers with a thicker periderm, while pectin staining demonstrated that KPhi treatment induced a reinforcement of the wall of storage parenchyma cells. Both compounds elicited the production of H2O2, which is usually involved in cell-wall remodelling and stiffening reactions while only KPhi caused an increase of the total content of phenolic compounds. A two-phase digestion in vitro assay showed that treatment with KPhi determined a significant decrease of the starch hydrolysis rate in potato tubers. This work highlights the ability of cell wall architecture in modulating starch accessibility to digestive enzymes, paving the way for new agronomic practices to produce low GI index potatoes.

Anti-Proliferative Effect of Rosmarinus officinalis L. Extract on Human Melanoma A375 Cells.

Rosemary (Rosmarinus officinalis L.) has been used since ancient times in traditional medicine, while nowadays various rosemary formulations are increasingly exploited by alternative medicine to cure or prevent a wide range of health disorders. Rosemary's bioproperties have prompted scientific investigation, which allowed us to ascertain antioxidant, anti-inflammatory, cytostatic, and cytotoxic activities of crude extracts or of pure components. Although there is a growing body of experimental work, information about rosemary's anticancer properties, such as chemoprotective or anti-proliferative effects on cancer cells, is very poor, especially concerning the mechanism of action. Melanoma is a skin tumor whose diffusion is rapidly increasing in the world and whose malignancy is reinforced by its high resistance to cytotoxic agents; hence the availability of new cytotoxic drugs would be very helpful to improve melanoma prognosis. Here we report on the effect of a rosemary hydroalcoholic extract on the viability of the human melanoma A375 cell line. Main components of rosemary extract were identified by liquid chromatography coupled to tandem mass spectrometry (LC/ESI-MS/MS) and the effect of the crude extract or of pure components on the proliferation of cancer cells was tested by MTT and Trypan blue assays. The effect on cell cycle was investigated by using flow cytometry, and the alteration of the cellular redox state was evaluated by intracellular ROS levels and protein carbonylation analysis. Furthermore, in order to get information about the molecular mechanisms of cytotoxicity, a comparative proteomic investigation was performed.

Proteomic analysis of apricot fruit during ripening.

Ripening of climacteric fruits involves a complex network of biochemical and metabolic changes that make them palatable and rich in nutritional and health-beneficial compounds. Since fruit maturation has a profound impact on human nutrition, it has been recently the object of increasing research activity by holistic approaches, especially on model species. Here we report on the original proteomic characterization of ripening in apricot, a widely cultivated species of temperate zones appreciated for its taste and aromas, whose cultivation is yet hampered by specific limitations. Fruits of Prunus armeniaca cv. Vesuviana were harvested at three ripening stages and proteins extracted and resolved by 1D and 2D electrophoresis. Whole lanes from 1D gels were subjected to shot-gun analysis that identified 245 gene products, showing preliminary qualitative differences between maturation stages. In parallel, differential analysis of 2D proteomic maps highlighted 106 spots as differentially represented among variably ripen fruits. Most of these were further identified by means of MALDI-TOF-PMF and nanoLC-ESI-LIT-MS/MS as enzymes involved in main biochemical processes influencing metabolic/structural changes occurring during maturation, i.e. organic acids, carbohydrates and energy metabolism, ethylene biosynthesis, cell wall restructuring and stress response, or as protein species linkable to peculiar fruit organoleptic characteristics. In addition to originally present preliminary information on the main biochemical changes that characterize apricot ripening, this study also provides indications for future marker-assisted selection breeding programs aimed to ameliorate fruit quality.